Spark-plug.



J. 6. AND H. W. AMBROSE. V

SPARK PLUG.

APPLICATION man 0mm. 191a Patented Oct. 21, 1919.

, inf/4m J'ulmmfg UNITED sTAfrEs PATENT osmos- JENNINGS GRANT AMBROSE AND HENRY W. AMBROSE, OF LOMA PORTAL, CALIFORNIA.

SPARK-PLUG.

,1 3. Specification 6r Letters Patent. 'p t t l Oct, 21, 1919,

Substitute for application Serial No. 108,690, filed July 11, 1916. This application filed December 1-0, 1918.

Serial No. 266,087.

72) all who may 009 bores 11 and 14 cooperating to define an inllo it known that we, Jassmos Cease terual shoulder 15 in the casing. Below the A muuosa and llnxuY lV. A Mimosa, citizens shoulder 15, the casing 9 is internally of the United States, residing at Loma lorthreaded as shown at 16. The upper end of la], in the county of San Diego, h'tate of tin-,casiug E) is downwardly and outwardly California, have invented a new and useful hove ed as shown at. 1?. in the casingtl, near Spark-Plug, ofwhich the following is a to its lower end, openings 1-5, are. formed.

specification. Screws 8 are threaded into the lower end of The device forming the subject nultter of the casing l), the screws H constituting electhis application is a spark plug, and one trodes. The screws 8 are all of the same 65 object of the invention is to provide a device length, but the openings in the casing 9 of this type in wflch the thimble which carwhich receive the heads 0." the screws are ries the porcelain body of the plug is spaced countersunk to different depths so that one from the casing portion of the plug to define screw H projects inwardly to a less distance an air chamber which prevents excessive. than a second screw, the second screw no 70 heating and a breaking of the )orcelain jecting inwardly a less distance than a t lll'tl body, cmuhined with means whereby moisscrew. Any desired number of screws or ture or water will be prevented trom eLtcrclectiodes 8 may he provided. The lower ing the chamber, end of the casing 9 is cut away as shown 21" Another JlJjBCt of this invention is to proat 1 9. 75 .itle, a. spar]; plug in which the electrodes eo- The numeral denotes a t-hnnble winch, operate in a novel manner. preferably, is made ot metal. The lower end It is withn the profince of the disclosure of the thimble 20, indicated by the. reference a improve generally and to enhance the 'lltll'lh'cl' 21, is of less diameter than the 26 In. !ity of d vicesof that type to which the body portion of the. thimblc and is threaded a0 press-1 t invdiition apperta ns. into the part; ill of the casing 9. Since the Vita the above and otller objects in view, lower end 2| of the thimble 2l) is of smaller which will appear as the description prodiameter than the body portion of the thinlcoeds. the invention resides 'n the comhinable, there is formed ashoulder 22 which tiolt ind arrangement of pants, and in tl-e. deabuts against the, shoulder 15 of the cas- 85 tails of construction hereinaftc: described ing. The thimhe 20 is provided with an enand claimed, it being m dal-stood that larged wrench head 23, spaced from the upchangcs in the precise embodnnent of the iuper end of the casing 9, and undercut as vention herein disclosed can hp made, within shown at 24, the wrench head 23 including the scope of what is claimed, without dcparta conical apex 5, having an internal shoul- 90 ing from the spirit of the. love ition. der 25. At this point it should he observed In the accompanying drawn gs: hat the outer surface of the thimble 20 is F ignre 1 1s a longitudinal section showin maced from the inner surface of the ena spark plug construotml n accordance wit-1 larged upper bore 11 of the casing 9, so as the invention; Fig. 2 is a side elevation of to define an air chamber 26, the space he- 95 the plug; Fig. 3 is an end elevation of the tween the wrench head of the thimble 20 plug; Fig. 4 is a cross section on the line and the upper end of the casing 9 constitut- 4-4-0f Fig. 1. ingan inlet 6 for the air chamber-2'6. In carrying out the. present invention, The numeral 4 denotes a body made out there is provided an outer casing J, which, of porcelain or other suitable insulating m-aloo preferab y, is made of metal. The casing l) tonal, the body being received in the thimis externally screw-threaded as shown at 10, bie 20. Adjacent its upper end, the hotly so that it may be mounted in the head of an is reduced in die net/e1 to form a shoulder 27 internal combustion engine, or be. otherwise which abuts against the shoulder 25 cf the located at the proper point, the casing t. in.- thimhle 20. The body 4 projects upwardly IUJ eluding a wrench head 7, whereby the casing above the part 5 of the thimhle 20, and is may be rotated readily. The casing has provided with an axial hore 28,enlargcd iu an enlarged upper bo"e 11 which isoutvvardtu termediatc itsends. and adjacent the upper flared at its up mr gnd WWI] at 13. the 1 Fiat of the' body 4, to form a recess :30, casing including a smaller lower bore ll, the ln lhe bore #8 of the liodyil is located a He thim'ble being spaced from the casing to define an air chamber, aridthe thimble ineluding an enlargement spaced from the end of the casing and extended outwardly above the air chamber to serve as a protection therefor, the enlargement being undercut.

4. A spark plug comprising e casing; a thimble in the casing; a body in the thimble; end an electrode carried by the body, the thimble being Spam from the casing to define an air chamber, and the thimble including an enlar' ement spaced from the end of the cesin an extended outwardly above the air chem er to serve as a protection therefor, said end of the casing being outwardly be veled, and the enlargement being undercut;

5. A spark plug comprising a casing; a

main electrode within the' casing, and extended longitudinally of the casing; and secondary electrodes movably carried by the casing and disposed transversely of the easing, the inner ends of the secondary electrodes being spaced at different distances from the main electrode, all of the secondary electrodes being of the same length, the sec ondary electrodes being provided with heads, and the casing being proi'ided with seats which receive the heads, the seats being of different depths.

In testimony that we claim the foregoing as our own, We have hereto afiixed our signatures.

JEHNINGS GRANT AMBROSE. HENRY V. AMBROSE. 

